Thursday, July 26, 2012

The power of scientific images

One of the leading news stories on Canada's CTV News website today was the sensationally-titled "Freak event: Ice melting nearly all over Greenland".  It was accompanied by the image shown to the left.  The map on the left half of the image looks like our usual mental picture of Greenland, with ice (white, naturally) covering most of the area.  It should be obvious that the image on the right half cannot possibly represent an ice-free Greenland (if Greenland's ice sheet had melted away, I'd be typing this right now underwater :-)   Rather, it shouldn't be hard to figure out that the warm colours must represent something like an increase in melting or melt rate.

Shown to the right is the original image from the story at the NASA website; note the legend at the bottom, which was cropped from the CTV image.  This is a perfect example of what can happen when a scientific image escapes into the public domain, where there is no guarantee that the complete story told by the image will be preserved. Of course a change in the melt rate is worrisome, but without its caption the image can easily be misinterpreted as presenting a more dire situation.  I for one will not be surprised if climate change deniers use the CTV story as a perfect example of how the media (and, naturally, its commie-pinko overlords) conspire to mislead the public about the severity of climate change. 

Who is to blame?  Well, CTV, for their sensationalistic headline and thoughtless cropping. But also  the image jockeys at NASA, usually careful about their PR (and for good rea$on$), for not considering how easy it would be to misrepresent this particular image.

Update: And so it begins -- below is a post from a user on the CTV website regarding the above story:

I hope people realize some visual mind cuing is going on here.. we associate white with snow and therefore see the red as the snow is gone.. These two red colors only represent different degrees of melting... I read the original report which printed the color index.. suspiciously missing in this photo... only the grey areas are snow free and that has not changed much .. the colors pink and red represent 'probable' melting and some surface melting (respectively) 'Some' melting meaning a few inches of surface snow on an unchanged depth of ice pack. I am willing to face facts.. but not ones twisted towards a desired opinion.. had the scale been in shades of one color it would have been much less 'dramatic' and much more accurate .. barely one shade different. I am not saying what to believe here.. but ask people to be aware that agendas are showing with how this map is being presented.

Tuesday, June 5, 2012

Welcome Nova!

Congratulations to BSL postdoc Jonathan Mynard and his wife Lorrae on the birth of their daughter Nova Therese, formerly known as Mini Mynard.  Hmm, I see: Mini - Mine - Nine - None - Nove - Nova.  OK, so I made up Nove, but turns out it's a Latinate word.  (Can you tell I'm procrastinating :-)

Thursday, May 31, 2012

Sound progress

Thanks to Roberta Buiani for her adept summary of our collaborative sonification project, which BSL's Dolores Steinman presented at the Subtle Technologies Festival in Toronto last weekend.  Next stop is the Supersonix conference in London (UK), where Dolores will meet up and present with our GreenOn collaborators, Riccardo Castagna and Valentina Margaria.

Blogstipation vs. Blogorrhea

Dear Reader,

On my way to work today, I was thinking about how I don't update this blog very often because I want to be careful, thorough and accurate about what I say. This came about from the previous post about hypothesis testing, after I realized I'd spent (or maybe wasted?) at least a couple of hours last night, and some time this morning, on so few words, all because I wanted to be sure I was accurately reflecting on a paper that I'd guzzled down the night before; and I am still wondering if I'd acted too rashly.

 So I had an idea about writing a blog post about what I feel (fear) might be the tendency of prolific Web 2.0'ers to sacrifice thoroughness and accuracy in the name of speed and timeliness, leaving the rest of us to separate the wheat from the chaff. But then I thought, no, maybe I'm being too harsh and unfair, and I'd better think about it some more and do some research before smearing what might well be a majority of writers who just happen to have the knack for getting their candid cogitations down cleanly, coherently and correctly. Whereas I am overly cautious and circumspect, for example having now spent almost an hour editing a shallow blog post about why I'm not cut out for writing blog posts on a regular basis.

Or perhaps I'm just disappointed that the oh-so-clever terms I'd come up with on my way to work today -- blogstipation, blogorrhea, and twitterhea -- are already in the Urban Dictionary.

Blogstipatedly yours,


Hypothesis Testing

Web of Science has a great service that notifies me when a paper I've authored has been cited.  This is a great way to find out who is reading -- well, at least who is citing -- one's work.  But it came as a bit of a surprise to find our 2008 paper on parent-aneurysm angle cited in a paper entitled "The Role of Hypothesis in Biomechanical Research".  Hmm, I thought, that can't be good...

The bottom line is that the authors looked at 100 papers published in The Journal of Experimental Biology and the Journal of Biomechanics and observed that, while the majority purported to test a hypothesis, many actually did not.  The authors go one speculate about a number of possible motives for such "window dressing".

I was somewhat relieved to find that our paper was only "strongly suspected" of having such a presentational hypothesis. Unfortunately the authors did not pick our paper as one of the four cases that they used to justify their suspicions, but they did later highlight the kinds of things that gave them pause:
  1. In a small number of cases, the data did not appear to bear on one or more of the hypotheses that it was the stated intention to test.
  2. In the other cases, which were more common, one of the stated aims of the paper was to test a hypothesis that was widely accepted to be true or false
  3. A sub-set of these cases were hypotheses that we thought to be post hoc; typically, in such cases, we registered only a suspicion.
I thought our paper was very clear about its motivations, namely that after we had observed "distinct types of intra-aneurismal hemodymamics" in two patient-specific cases we'd previously studied, we "hypothesized that these two distinct 'hemodynamic phenotypes' were primarily the result of the angle which the parent artery makes relative to the nominal center of the aneurysm bulb, independent of the bulb shape itself".  We then stated that we would "test this hypothesis using an idealized basilar tip aneurysm model in which [this angle] could be controlled independently," and did just that.

In the Discussion we did say "it can be hypothesized that Type II flow would create a higher associated risk of rupture", but this was intended to be conditional -- perhaps we should have said "could" instead of "can" -- but we made no claims about testing this.

So I'm not really sure why those authors were suspicious of our motives. Our data, from an idealized aneurysm model with varying angles, obviously bore on our hypothesis.  I'm pretty sure our hypothesis was novel, but even if it wasn't it certainly was not widely accepted to be true or false. Finally, we did not go through the trouble of running careful simulations on a series of idealized models with progressively angled bulbs only to hypothesize about it after the fact.

Oh well, as Oscar Wilde, er, hypothesized, the only thing worse than being talked about is not being talked about.

Thursday, May 24, 2012

Subtle Technologies Festival

We look forward to this weekend's Subtle Technologies Festival here in Toronto, where BSL's Dolores Steinman will be presenting, on Saturday, our sonic explorations with Green On's Riccardo Castagna and Valentina Margaria, and Torino's Master of Helicity, Diego Gallo. On Sunday Dolores will also participate in a panel discussion following the premiere of the film, BioArt.

Monday, May 14, 2012

Congratulations to Luis Aguilar, PhD

Felicitaciones to Luis Aguilar, who today successfully defended his PhD thesis, "Towards Real-Time Simulation of Ultrasound Systems". Many thanks to co-supervisor Richard Cobbold, and to examiners Guy Cloutier, David Goertz and Wayne Johnston for giving Luis his money's worth!

Tuesday, May 1, 2012

A Prof's Life

Stumbled across this blog post of Fil Salustri's, which I think nicely describes the life of a Professor. Fil and I were grad students together at UofT, and had both done our undergrad degrees there.  He'd started two years earlier, so whenever I thought I'd been at UofT for too long -- and I was there for nearly a decade -- I had Fil to look up to (sorry Fil, couldn't resist :-)

Monday, April 30, 2012

Congratulations to Kristian Valen-Sendstad

Congratulations to BSL postdoc Kristian Valen-Sendstad, who has been awarded a Government of Canada Post-Doctoral Research Fellowship for his studies of "turbulence" in cerebral aneurysm hemodynamics.

Kristian is also just back from an international vascular biomechanics conference in Atlanta, where his talk, "Is CFD Misleading Us About the Nature of Wall Shear Stresses in Cerebral Aneurysms?" generated a lot of interest and discussion, as well as lots of ideas for us to pursue here at the BSL.

Paper Published: Geometric Characterization of Cerebral Aneurysms

Congratulations to BSL collaborator Marina Piccinellli on the publication of "Automatic neck plane detection and 3D geometric characterization of aneurysmal sacs".  This VMTK paper had a long germination, starting several years ago during one of my trips to work with Luca Antiga in Bergamo, through to a rather long and tortuous review process.  On the other hand, once it was accepted it showed up online in record time!

In the spirit of our open-source philosophy, the Aneurisk models used in this study are available online, and VMTK code should appear soon.  We hope that this will spur some kind of standardization in the geometric definition of cerebral aneurysms, and so allow the kind of large, multicenter studies that are sorely needed.

Sunday, April 15, 2012

Paper Accepted: Improved Prediction of Disturbed Flow

Congratulations to BSL PhD student Payam Bijari, whose paper "Improved prediction of disturbed flow via hemodynamically-inspired geometric variables" was recently accepted by the Journal of Biomechanics.

The gist of this study is that insight into the actual relationship between geometry and hemodynamics can be fed back into the definition of geometric variables for their use as practical surrogate markers of disturbed flow.  First stop: carotid bifurcation.  Next stop: cerebral aneurysms (or Greenwich Village :-)